The present invention relates to a seat having a backrest and an adjustable spinal or vertebral support.
There are various forms of seats with a backrest and an adjustable spinal or vertebral support for supporting in particular the intervertebral discs, comprising an adjusting element which acts against the rear surface of the upholstery cushioning of the seat and which is adjustable in respect of the depth of the backrest. However, such supports are only adjustable in respect of depth, and they are at a fixed position in the heightwise direction of the backrest.
However, the spinal columns of human beings are not all the same. More particularly, human spinal columns can be divided into various types, and for this reason support for the spinal column when a person is in a sitting position should be provided not only at various depths but also at different heights, if the supporting action is to be of optimum efficiency from the medical point of view.
In addition, even with one and the same type of spinal column, it is desirable to be able to alter the load on the intervertebral discs, in order to avoid continuously loading individual discs.
The above-discussed problems are particularly important for the drivers of utility or commercial vehicles, who often have to spend up to eight hours and even more in a sitting position, in each day.